Honestly, no matter how you spin it, you don’t trust him. My bf leaves his phone around me and I know the code. But I have never gone through it because I trust his loyalty to me. My bf and I have the understanding that if we ever feel like we need to snoop then trust is gone and if we don’t have trust there is no point staying together. I’ve been in your position with past relationships, it’s never worth it. Communicate your fears, and move on from the relationship you obviously can’t bet on. It’s hard, it sucks, and it will hurt. It’s also obviously very unhealthy, and you both deserve more.